-10=-5y(y+9)

Solution for -10=-5y(y+9) equation:

-10=-5y(y+9)

We move all terms to the left:

-10-(-5y(y+9))=0


We calculate terms in parentheses: -(-5y(y+9)), so:

-5y(y+9)

We multiply parentheses

-5y^2-45y

Back to the equation:

-(-5y^2-45y)


We get rid of parentheses

5y^2+45y-10=0

a = 5; b = 45; c = -10;
Δ = b2-4ac
Δ = 452-4·5·(-10)
Δ = 2225
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{2225}=\sqrt{25*89}=\sqrt{25}*\sqrt{89}=5\sqrt{89}$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(45)-5\sqrt{89}}{2*5}=\frac{-45-5\sqrt{89}}{10}
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(45)+5\sqrt{89}}{2*5}=\frac{-45+5\sqrt{89}}{10}
$